1. Field of the Invention
This invention relates to a foam it mount having an electric conductive layer over a light blocking layer or coating, and method of applying same to the foam window mount, and more particularly, to a foam window mount having an electric conductive coating over a light blocking layer having a visible light transmission of less than 40% and preferably zero percent over outer facing surfaces of the foam mount and a decorative layer or coating over inner surfaces of the foam mount, and methods of applying the layers.
2. Discussion of the Technical Problem
At the present time there is a desire to provide electronic shielding around the body of commercial aircrafts such that electronic signals to and from electronic equipment of the passengers, e.g. cell phones and computers within the commercial aircraft, are only transmitted by and received through the antenna of the aircraft. One of the advantages of this arrangement is the elimination of uncontrolled transmission of signals through the windows of the aircraft, which transmitted signals can interfere with transmitted signals required to operate the aircraft. As is appreciated by those skilled in the art, to attain this goal it becomes necessary to prevent transmission of the signals through the cabin windows and through the door windows of the aircraft.
In one approach to accomplish this goal, a window pane having an electric conductive layer is mounted in a foam mount, e.g. a foam window mount having an electric conductive layer. The window pane can be an electrochromic window, or one or more glass sheets having an electric conductive layer or film over the major surface of one or more of the sheets. More particularly and as is known in the art, the electrochromic window includes an electrochromic medium between two spaced electrodes. Each of the electrodes includes an electric conductive layer or film on a major surface of a glass sheet. The electric conductive layer or film provides a radio frequency (“RF”) shielding.
The outboard surface of the foam mount has an electric conductive layer, e.g. an RF shielding layer or coating, and the inboard surface of the foam mount is coated with a non-electrical conductive decorative paint to compliment the decor of the aircraft interior. A detailed discussion for painting the foam mount with the electric conductive layer or coating and the non-electric conductive layer or coating is presented in U.S. Pat. No. 8,105,845.
The foam mount having the window pane is positioned in the window opening of the aircraft between an outboard structural ply and an inboard protective overlay sheet. The conductive layer on the foam mount is electrically connected with the aircraft body to connect the electric conductive layer of the foam mount to the electric ground of the aircraft. With this arrangement, the electric conductive layers of the electrochromic window and the electric conductive layer of the foam mount provide an RF shielding over the window opening hi the body of the aircraft.
Although the painting techniques disclosed in U.S. Pat. No. 8,105,645 are acceptable for applying two different coating layers on a foam mount, the coated foam mount has limitations. More particularly, the electric conductive layer and the non-electric conductive decorative layer is expected to have a visible light transmission of greater than 45%. The result is a portion of the visible light impinging on the electric conductive layer passes through the electric conductive layer, through the foam mount, and through the decorative layer. The foam mount transmits diffused light, i.e. the foam mount transmits visible light but causes sufficient diffusion of the visible light to prevent perception of distinct objects.
As can be appreciated by those skilled in the art, the foam mount passing diffused visible light is not decoratively acceptable, and is disruptive to the airline passengers. It would be advantageous, therefore, if visible light impinging on the electric conductive layer was prevented from passing through the foam mount.